Swiss pilot Raphael Domjan beat the altitude record for a solar-powered electric plane in a flight that took him soaring to 9,521 metres, his team announced Wednesday.
The SolarStratos plane made the landmark flight from Sion airport in southwest Switzerland on Tuesday, taking advantage of warm air thermals to go beyond the record that has stood for 15 years.
The certified altitude record for a solar plane stands at 9,235 metres (30,298 feet).
The achievement is “one of those unforgettable peaks that define great human and technological adventures”, the SolarStratos mission said in a statement.
Domjan’s flight lasted five hours and nine minutes.
“I share this moment of joy with all the people who have been preparing for this achievement for years,” the 53-year-old “eco-explorer” said.
The data will be sent to the World Air Sports Federation governing body, which will decide whether to validate the new record.
“It is the pressure altitude corrected to standard density altitude that is recognised as the official reference for aviation altitude records,” the SolarStratos team said.
Capturing imaginations
Domjan is aiming to be the first to take a solar-powered plane above 10,000 metres, flying at the same altitude as airliners.
If this barrier is broken, the team hopes to go on and make a first manned solar-powered flight into the stratosphere, which at Switzerland’s latitude begins at around 12,000 metres.
“This achievement marks a major milestone on the path toward reaching the stratosphere using only solar power — and already fulfils the mission’s goal: to capture imaginations with emblematic, spectacular challenges that promote solar energy and the protection of our biosphere and planet,” SolarStratos said.
The front-mounted single propeller plane, registration HB-SXA, is made of carbon fibre to ensure lightness and strength.
SolarStratos is 9.6 metres long, and its huge wingspan of 24.8 metres accommodates the 22 square metres of high-spec solar panels topping the wings, and allows for flying at low speeds.
The plane can take off at low speeds, from 50 kilometres per hour upwards. Its maximum speed is 140 kph, while its cruising speed is around 80 kph.
The dream of flight
In 2012, the pioneering Domjan became the first person to sail around the world in a fully solar-powered boat.
“It’s important to demonstrate what we can achieve with solar energy,” the adventurer told AFP.
“The dream of flight is probably the oldest dream of mankind. My goal is to show to the young generation of today and tomorrow that tomorrow it will still be possible to fly without burning any fossil energies, with emitting any carbon dioxide.
“This is what we want to achieve: it’s really to show that the world of tomorrow can be better than what we have today.”
Two-stage ascent
A warm-up flight on July 31 got to 6,589 metres, surpassing the plane’s previous best in 2024.
A first attempt on Friday was quickly abandoned when the forecast thermals failed to materialise, saving the batteries for Sunday when the plane got to 8,224 metres.
During the first phase of record attempts, the aircraft has to make maximum use of rising warm air currents to climb to around 4,000-5,000 metres.
It then has to recharge its batteries at this altitude before climbing again.
If the flight is to be certified as a record, all the energy used during the flight must have been produced by the solar cells.
Before take-off, the batteries must be fully charged using solar energy, and the plane has to land under its own power — it cannot glide back in on zero charge — and have at least 16% charge in the batteries.
The current record was set in 2010 by the Solar Impulse experimental plane, with Swiss pilot Andre Borschberg at the controls.
The project’s promoter, Swiss explorer Bertrand Piccard, then built a second solar aircraft which successfully made a round-the-world trip, in stages, between March 2015 and July 2016.
